1. Field of the Invention
The invention relates in general to a computer system for supporting multi-processes . More particularly, the invention relates to an apparatus and a method for supporting multi-processors and distinguishing the type of the central processing unit.
2. Description of the Related Art
The motherboard manufactures have to design a specific motherboard for each types of central processing unit (CPU). This is because the CPU socket, the pin function, the system clock frequency and the supplied voltage for each CPU are different. Therefore, a common mother cannot be used. Even when different kinds of CPU's use the same CPU socket, the functions given by each pin, the system clocks and the supplied voltages are different, so that a common motherboard cannot be applied.
In U.S. Pat. No. 5714873, a method to automatically supply correct voltage to the CPU is provided. The VOLDET pin of the CPU is used to transmit a signal to a selector, so as to control the voltage regulator to output a proper voltage to the CPU. However, this is only suitable for the application of a CPU with the VOLDET
The conventional CPU's, the Coppermine and Tualatin type, fabricated by the CPU manufacture Intel associates with 370 pins socket, so called Socket-370 CPU Between two types of CPU, there are 23 pins with different functions (referring to Table 1). The core voltage and supply voltage used for these two CPU's are different (Coppermine type followed VRM8.4, and Tualatin type followed VRM8.5 VCC—CORE specification for core voltage, as well as, Coppermine type supplied 1.5 V, Tualatin type supplied 1.2 V for supply voltage). Therefore, these two types of CPU cannot service at a common motherboard.
TABLE 1PinCoppermineTualatinE21RSVDRSVDE27SLEWCTRLVSSG37RSVDVTTN37RSVDNCHCTRL[VTT]Q33RSVDRSVD[NCHCTRL]W35RSVDRSVD[VTT]X2BR#1RSVDX4RESET2#VSSX34VCCVTTY33CLKREFCLK#Z36V—2.5RSVDAB36V—COMSVTTAD36V—1.5VTTAE37FLUSH#FLUSH#AG1RSVDVTTAH4RSVDRESET#AJ3VSSRSVD(RESET#)AK4VSSVTT—PWRGDAK22GTLREF7CMOSREFAK36VSSVID25MVAL1VSSRSVDAM2RSVDVSSAN3VSSDYN—OD(BUSEL)